Air operated tool with rear exhaust



March 24, 1970 P. A. SNIDER AIR OPERATED TOOL WITH REAR EXHAUST Filed June 18, 1968 2 Sheets-Sheet 1 Ilkmm mm Om mm 0 mm PHIL/P A. SN/DER 5 We b ATTORNEYS mm N March 24, 1970 P, sNlD 3,502,158

AIR OPERATED TOOL WITH REAR EXHAUST Filed June 18, 1968 2 Sheets-Sheet 2 INVENTOR PHIL IF A. S/V/DER A'ITORNEYS United States Patent Int. Cl. B23q /06; B23]: 45/04; F01d 15/06 US. Cl. 17312 7 Claims ABSTRACT OF THE DISCLOSURE An air operated tool having air exhaust passages extending from the air motor to the rear of the tool axially oflFset from the air inlet passages and control valve therefor for directing the exhaust air away from the work. An overhose may be telescoped over the air supply hose for directing the exhaust air further from the work while reducing the noise level of the tool.

BACKGROUND OF THE INVENTION This invention relates generally as indicated to an air operated tool including a high speed air motor driven by air which is exhausted through the rear of the tool in a new and novel manner.

It is common practice to direct the exhaust air from an air operated machine tool and the like along its drive shaft toward the working area of the tool to blow away dirt and other foreign matter as disclosed for example in the patent of Roland E. Doeden, US. Patent No. 2,830,- 560. However, there are occasions when the blowing of grinding dust, chips and the like is not permitted or at least is very undesirable. In that event, the air is usually exhausted radially from the side of the air motor, which is not always a very satisfactory solution especially where the tool is quite compact and the air exhaust is close to the work, or there is dust around the tool which is continually stirred up by the exhausting air.

SUMMARY OF THE INVENTION It is accordingly a principal object of this invention to provide an air operated tool in which the air is exhausted from the rear of the tool as far from the work as possible by providing exhaust passages axially offset from the air inlet passage and control valve for the incoming air. An overhose may be telescoped over the air supply hose for directing the exhaust air further away from the work. This also greatly reduces the noise level of the tool.

Another object of this invention is to provide an air operated tool of the type described with a compact air motor governor for controlling the speed of the air motor without necessitating a change in the size and appearance of the tool despite the provision of the rear exhaust passages therein.

These and other objects of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the in vention may be employed.

BRIEF DESCRIPTION OF THE DRAWING In the annexed drawing: FIG. 1 is a side elevation of a preferred form of air operated tool constructed in accordance with this invention;

FIG. 2 is a fragmentary longitudinal section through the handle portion and rear end of the tool of FIG. 1, taken on the plane of the line 22 thereof;

FIGS. 3 through 6 are longitudinally spaced transverse sections through the tool of FIG. 2, showing the configuration and disposition of the air inlet and exhaust passages therein, taken on the planes of the lines 33 through 6-6, respectively;

FIG. 7 is a fragmentary longitudinal section similar to FIG. 2 but of another form of air operated tool in accordance with this invention; and

FIGS. 8 and 9 are longitudinall spaced transverse sections through the tool of FIG. 7, taken on the planes of the lines 88 and 99, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawing and first to the form of the invention illustrated in FIGS. 1 through 6, there is shown an air operated tool 1 having a generally cylindrical housing 2 containing an air motor 3 of conventional type suitably connected at its forward end to a chuck element 4 on which may be mounted a grinding element or the like for rotation by the air motor. For a more complete discussion of a typical air motor and chuck element which may be used herein, reference may be had to the aforementioned Doeden US. Patent No. 2,830,560.

Attached to the rear of the housing 2 as by means of a threaded coupling 5 is a tubular handle 6 having a handle extension 7 threaded into the outer end thereof, all which form an extension of the housing 2. The cou pling 5 is also tubular and contains a bushing 8 which defines with the adjacent end of the air motor 3 a cavity 10 for receipt of a speed control governor 11 which may be threadedly connected or otherwise attached to the rotor shaft 9 of the air motor 3 for rotational movement therewith.

The speed control governor 11 is desirably of the type shown in my copending application Ser. No. 686,599, filed Nov. 29, 1967, which because of its compact nature, requires very little space and yet is very eflicient and eifective in controlling the speed of an air motor. The main parts of the speed control governor 11 are the base plate 12, a pair of valve blades 13, 14 pivotally mounted on the base plate, and a spring 15 interconnecting the blades 13, 14 urging them apart. For a more complete discussion of the details of construction and operation of the speed control governor 11, reference is had to my aforesaid copending application Ser. No. 686,599.

The bushing 8 has a rearwardly projecting cylindrical hub portion 18 with an outwardly tapering shoulder 19 adjacent the forward end of the cylindrical hub portion 18 which provides a seat for the conical forward end 20 of a divider sleeve 21 which telescopes over the hub portion 18 and has square sides which define with the inner wall of the handle 6 plural passages 22 therebetween. The rear end 23 of the divider sleeve 21 is also preferably tapered for mating engagement with the tapered forward end of a central passage 24 in the handle extension 7 to provide fluid communication between such central passage 24 and a central passage 25 through the divider sleeve 21.

Such central passage 24 in the handle extension 7 desirably does not extend all of the way through the handle extension, but rather extends from opposite ends thereof toward the middle where it is interrupted, and a pair of diametral passages 26', 27 are provided, one diametral passage 26 communicating with the forward portion 24' of the central passage 24 and the other diametral passage 27 communicating with the rearward portion 24 of the central passage 24. Telescoped over the handle extension 7 is an air throttling sleeve 28 which is provided with an internal groove 29 having a length sufficient to communicate the diametral passages 26 and 27 with each other when in the forward position shown in FIG. 2, and block communication therebetween when moved to the rearward position shown in phantom lines. Longitudinally spaced apart shoulders 30 and 31 on the handle 6 and handle extension 7, respectively, limit the movement of the throttling sleeve 28 between its forward and rearward positions, and O-rings 32 may be inserted in internal grooves 33, 34 in the air throttling sleeve 28 adjacent the internal groove 29 therein for providing a fluid tight seal with the outer surface of the handle extension 7.

Incoming air for driving the air motor 3 is supplied to the rearward portion of the central passage 24 through an air supply hose 35 threadedly or otherwise suitably connected thereto. With the air throttling sleeve 28 in the forward position shown in FIG. 2, the incoming air will pass through the rear portion 24 of the central passage 24, diametral passage 27, annular groove 29, diametral passage 26, and forward portion 24' of the central passage 24 into the central passage 25 of the divider sleeve 21, from whence it will pass through the hub portion 18 of the bushing -8 for flow through and around the speed control governor 11 and into the air motor 3 for driving the same in conventional manner. An air nozzle 36 may be threadedly received in the hub portion 18 for controlling the clearance between the air nozzle 36 and governor blades 13 and 14 as desired. To block the air flow to the motor 3, the air throttling sleeve 28 is simply moved rearwardly to the phantom line position.

The exhaust air from the motor 3, instead of being discharged forwardly toward the working area of the tool or radially outwardly through the housing 2 in known manner, is directed into a pair of passages 40 (see especially FIG. 3) formed by the annular inner wall of the housing 2 and opposite flat sides 41 of the bushing 8. These passages 40 communicate with the plural passages 22 between the annular inner wall of the handle 6 and outer square sides of the divider sleeve 21 for discharge from the rear of the tool away from the work where it will not blow grinding dust, chips, and the like through plural longitudinal passages 42 in the handle extension 7 axially offset from the air inlet passages 24, 26 and 27. An overhose 43 may be telescoped over the air supply hose 35 and suitably connected to the rear of the tool 1 as by providing a flanged coupling 44 on the forward end of the overhose 43 which is adapted to be received in an annular recess 45 and held in place by a snap ring 46 for further directing the exhaust air away from the work. The passing of the exhaust air through the overhose 43 also results in a substantial reduction in the noise level of the tool, which is even more greatly re duced by connecting the overhose to a manifold or the like, and the overhose may likewise be connected to a duct or manifold for exhausting the air out of the building if desired.

The air operated tool 1 shown in FIGS. 7 through 9 is quite similar to the tool 1 of FIGS. 1 through 6, except for the elimination of the handle extension 7, the change in configuration of the divider sleeve 21, and the substitution of a lever operated valve mechanism 50 for the air throttling sleeve 28 for controlling the flow of incoming air to the air motor 3'. Such valve mechanism 50 is fitted into a transverse bore 51 in the handle 6, which transverse 'bore communicates with a pair of longitudinal passages 52 and 53 in the handle 6, the passage 52 leading to the inlet port 54 to which the air supply hose 35 is attached, and the passage 53 communicating with the interior of the divider leeve 21'. The

valve mechanism 50 includes a tubular bushing '55 pressfitted or otherwise secured in the transverse bore 51 and having a valve member 56 slidable therein into and out of engagement with a seat 57 on the inner end of the bushing 55. The valve member 56 is biased into engagement with the seat 57 by a spring 58, and there is a lever 59 pivotally connected to the handle 6' which when moved against the handle 6 by squeezing engages an extension 60 of the valve member 56 to cause the same to move away from the seat 57 for permitting flow of air from the passage 52 to the passage 53 through the bushing 55.

Exhaust air is directed to an annular passage 61 between the handle 6 and divider sleeve 21 from whence it is exhausted to the rear of the tool through semicylindrical passages 62 between the handle 6' and opposite fiat sides on the rear end of the divider sleeve 21' and plural longitudinal passages 63 in the rear end of the handle 6' which are axially offset from the transverse bore 51 and longitudinal passages 52, 53 therein. Otherwise, the details of construction and operation of the tool 1' of FIGS. 1 through 9 are substantially the same as the tool 1 already described, and accordingly no further discussion of the same is thought to be necessary. The same numbers followed by a prime symbol are used to designate like parts.

From the foregoing, it will be seen that the tool of the present invention effectively exhausts the air from the air motor away from the work through exhaust passages leading to the rear of the tool which exhaust passages are offset from the air inlet passage and control valve. The exhaust air may further be directed away by an overhose telescoped over the air supply hose. Although the various forms of tools disclosed herein include a speed control governor, it will be apparent that the principles of the present invention could equally be used in a tool without such a governor if desired.

I therefore, particularly point out and distinctly claim as my invention:

1. An air operated tool comprising a housing, an air motor in said housing, a chuck element connected to the forward end of said motor for rotation thereby, a bushing contained in said housing and defining with the adjacent end of said motor a cavity, said bushing having a rearwardly projecting hub portion, and a divider sleeve in said housing telescoped over said hub portion with its forward end in seated engagement with said bushing and its rearward end in seated engagement with a wall in said housing, said bushing, divider sleeve and housing wall having air inlet passages therein communicating with each other through which air is permitted to pass into said cavity for driving said motor as aforesaid, the outer surface of said bushing and divider sleeve defining with the inner surface of said housing air exhaust passages which communicate with each other and with additional air exhaust passages through said housing wall for discharging the exhaust air from said motor through the rear of said tool, said additional passages in said housing wall being offset from said air inlet passage therein.

2. The tool of claim 1 further comprising a lever controlled valve means in said housing for controlling the flow of air through said air inlet passage therein, said additional passages in said housing wall being offset from said valve means.

3. The tool of claim 1 wherein said housing includes a handle and handle extension which contains said lastmentioned air inlet passage, said air inlet passage in said handle extension being interrupted intermediate its ends, and there are a pair of axially spaced diametral passages in said handle extension, one communicating with each of the ends of said air inlet passage in said handle extension, and an air throttling sleeve telescoped over said handle extension, said air throttling sleeve having an internal groove therein through which fluid communication between said diametral passages is selectively blocked 5 and established by axial movement of said air throttling sleeve.

4. The tool of claim 1 further comprising an air supply hose attached to the outer end of said air inlet passage in said housing through which air is supplied for driving said motor as aforesaid, and an overhose telescoped over said air supply hose and atached to said housing in communication with said air exhaust passages therein for directing the exhaust air away from said tool.

5. The tool of claim 1 further comprising a governor in said cavity mounted on said motor for controlling the speed of rotation thereof, and an air nozzle in said air inlet passage in said bushing through which air is admitted into said cavity, said governor including means adapted to be progressively closed in response to speeds of said governor above a predetermined level for reducing the air flow through said nozzle to control the speed of rotation of said motor, said nozzle being axially adjustable to vary the clearance between said governor and nozzle.

6. The tool of claim 1 wherein the inner wall of said housing surrounding said divider sleeve is annular and said divider sleeve has outer square sides which define References Cited UNITED STATES PATENTS 751,261 2/1904 Clarke 2533 X 888,506 5/1908 Kellow 173163 X 970,225 9/1910 Holden 173-18 X 1,862,223 6/1932 King 17312 2,492,966 1/1950 Ckola 2533 2,966,138 12/1960 Quackenbush 173169 X 3,299,781 l/l967 Law l73l69 X ERNEST R. PURSER, Primary Examiner US. Cl. X.R. 

